Multiple steam drum boiler



Nov. 8, 1932. v I J, COUTANT 1,887,182

MULTIPLE STEAM DRUM BOILER Filed Oct. 11. 1930 2 Sheets-Sheet 1INVENTOR:

Jv aw? A TTORNEYS- Nov. 8, 1932.

, AS C J. G. COUTANT 1,887,182

MULTIPLE STEAM DRUM BOILER Filed Oct. 11. 1930 2 Sheets-Sheet 2INVENTOR:

BY aAa GW d W mMfW Ki MA1 gawk A TTORNEYSZ Patented Nov; 8, 1932 PATENTOFFICE JAY GOULD COUTANT, OF NEW YORK, N. 'Y.

MULTIPLE STEAM DRUM BOILER Application filed October 11, 1930, SerialNo. 488,028, and in France October 14, 1929.

This invention relates to multiple steam drum boilers, and is useful inany steam boiler having two or more steam and water drums, such as thefollowing makes, Stirling,

Ladd, Connolly, Walsh & Weidner, Erie,

' Union, Vogt.

One object hereof is to permit greatly fluctuating steam demands, suchas occur in modern power houses, to be met without substantial orundesirable variation in the pressure of the steam delivered.

A specific object is to permit an increase in the output of dry steamfrom a given boiler, other conditions being the same. It is a wellrecognized disadvantage of known installations that substantial increaseof steam output above normal or averageincurs an undue increase of thepercentage of moisture or wetness of the steam for a given steampressure,

thus practically limiting the useful output of the boiler. With thisinvention, in some cases, the boiler may be enabled to deliver as muchas twice the output of steam of a given dryness and pressure.

Further objects include maintaining calm and quiet and at maximumdensity the water in each drum, and maintaining uniform level in theseveral drums. Other advantages of the improvement will be explained inthe fur 3 ther description or will be understood to those conversantwith the subject.

By way of explaining the principles and use of this invention referencewill first be made to certain prevailing conditions in the art. Up tothe present time, it has been the practice to provide a certain amountof boiler heating surface to produce a given amount of steam per hour,without allowance for certain contributing factors that control thedegree of dryness of steam. For illustration, the following facts arerecited.

1.All boilers, for example of the Stirling type, having more than oneoverhead drum for water storage and steam space are so arranged that thegreater part, and in the case of a three drum boiler about 60% of thesteam generated is liberated in the first or front drum; then passingthrough tubes to the sec- 0nd or middle drum, where about more 50 ,steamis liberated; and then passing to a third or rear drum, where thebalance of about 10% steam is liberated. As the steam passes from eachdrum to the succeeding drum, the velocity is there increased, and it isfurther accelerated in the last drum while flowing toward the finaloutlet. Also, in this class of boilers there is utilized the steam spaceof only one of the drums, namely the last drum, for the precipitation ofmoisture from, and the drying of, the outgoing steam, under the mostdisadvantageous conditions.

2.-The bank of boiler tubes in the first pass, or those tubes mostexposed to the ra diant heat of the fire, and in which most of the steamis generated, enter the front drum below the water level therein, andpermit the rate of flow of steam and water slugs to become greater thancan be relieved at high rates of steam output. The first drum becomesfilled with water and slugs of water are carried over to the next drum,causing an excess of moisture in the steam at the boiler outlet.

3.In the design of Stirling type boilers with all tubes entering thedrums below the water line, the steam and slugs of water discharged fromthe tubes shoot high into the steam space and prevent the precipitationof moisture from the outflowing steam.

4.Thus the water stored in the drums is maintained in a turbulent state,at low density and low hydrostatic head, which causes slow circulation,and prevents also the settling of solids in the water, causing dirtysteam.

5.The safety valves are usually connected on the same drum with thesteam outlet nozzles, namely the last or rear drum. Thus when the valvesoperate, the steam velocities in the rear drum are still furtherincreased.

6.When the front drum is substantially filled with water and the reardrum is substantially empty, at high rates of steam output, while havingpoor circulation and increase of solids in suspension, there is aprobability that the rear drum and tubes will be overheated.

7.It has been found that a too great water storage in the drums resultsin slow steaming,

and in fluctuations in steam pressure when loads vary.

The present invention eliminates the features of boiler design thatcause the abovementioned difiiculties, and operates by the followingprinciples and features.

1.The present invention maintains slow steam velocity in each drum, sothat moisture will be able to be precipitated, thus fully utilizing thepotential value of the steam space in each drum.

2.It provides the necessary drum volume to carry out the above statedfunctions in relation to the steam demands. By utilizing the upper halfof each drum for steam space and for the precipitation of moisture, andthe lower half for water storage, the water storage is not so large-asto prevent fast steaming or to cause fluctuations in steam pressure whenserving varying loads. It has been determined that about one cubic meterof drum volume should be provided for each 32000 kilograms of steamproduced per hour.

3.With this invention, when steam and water slugs enter each of thedrums above the water line, they discharge against a baflle, deliveringa quantity of water proportional to the steam output, so as thereby tomaintain a uniform water level in all the drums, and with the Water in arelative calm state and at a maximum density, assuring rapid circulationand the settling of solid matter.

4.-Safety valves are placed on more than one, or on all the drums, andare so arranged 4 that the steam velocity in the drums will not beincreased when the valves operate.

This invention also includes the principle and means of taking steamfrom multiple steam drum boilers, with outputs corresponding to thesteam space of each drum, also certain exterior and interior drum andcollector tube connections.

All of these features characterize this invention for designing orperfecting steam boilers to produce increase in the output of dry steam,which will be better understood from the accompanying drawingsillustrating the invention and the description following.

Fig. 1 is a diagrammatic vertical section taken through the drums of aconventional type Stirling boiler, equipped with dry pans, external andinternal tube connections, and safety valve outlets.

Fig. 2 is a vertical section at the drums of a modern semi-verti calwater tube boiler with external tube connections, some entering abovethe water level, and showing the entering tubes, bafiles and safetyvalve outlets.

Fig. 3 is a Vertical section at the drums of a different semi-verticalwater tube boiler with external tubes and collector connections.

Fig. 4 is afivertical section at drum of a modified design of highpressure two-drum, cross drum, forged steel sectional header boiler,equipped with external and internal tubes, collector connections andsafety valve outlets.

Fig. 5 is a similar section showing a safety valve outlet detail.

Fig. 6 is a similar section showing details of the dry pan in each drum;and Fig. 7 is a modified dry pan construction in similar view.

Fig. 8 is a top plan View, for example of the third or rear drum in Fig.1, showing the longitudinal spacing of-the various tubes, which spacingcarries through to all drums and the boiler.

Fig. 9 is a view similar to Fig. 4 but showing only portions of thedrums and upper header of Fig. 4, and with a modified arrangement ofconnections.

It is believed to be new to control as described the water storage spaceand the steam space in the drums as the contributin factors that governthe ability of a steam oiler to generate dry steam at a given rate ofoutput. For example, the conventional type of Stirling boiler utilizesonly one-third of the available drum steam space for the precipitationof moisture and consequent drying of the steam, namely the space in oneof the three drums, while the same boiler (Fig. 1), equipped accordingto the present invention, will utilize the steam space in all the drums.

For illustration, the boiler in Fig. 1 is filled with water to line O0,where it can be maintained substantially constant, due to the improveddistribution of steam and water to each of the three drums, 1, 2 and 3,in relation to the amount of outgoing steam.

The tube bank 4, in the first or front pass, is exposed to the hottestheat of. the fire, and generates approximately 60% of the total steam,17% of which may pass through the extreme lowest row of tubes 5, whichare extended through drum 1, then by tubes 6 delivering into the reardrum 3 against a louvre bafile 7.

The tube bank 4 also liberates directly to the front drum 1approximately 43% of the steam, 10% of which may subsequently passthrough tubes 9 to drum 3.

The second lowest row of tubes in bank 4 is shown carried through drum 1by extension tube 8 into the middle drum 2.

The middle bank of tubes 10 may generate 30% of the steam. and is showndischarging directly to drum 2. It is supplemented by that delivered bytube 8.

The rear or third tube bank 11, at the left of Fig. 1, generates say 10%of the steam and discharges wholly to drum 3, and approximates 37% ofsteam liberated in drum 3, considering that tube 5, 6 discharges alsodirectly into this drum. The pressures in the three drums being equal,the inlet orifices to each of the dry pans 12, which extend nearly thefull length each drum, offer equal resistance to outlet flow. Therefore,approximately rau 33 of the steam generated will be selected from eachdrum. Any unequal pressure between drums would be equalized by tubes 15,interconnecting the dry pan spaces. Safety valve outlets 13 are placedon each drum, so as not to increase steam Velocities from. any drum incase a valve should operate. The final steam outlet 113, is on the thirddrum 3, as usual.

There is a. dry pipe 14 located in the dry pan of drum 3 and connectedto steam outlet nozzle 113, which is for the uniform selection of steamin the dry pan over the length of drum 3. I

Fig. 2 shows a modern semi-vertical type of boiler the drums of whichare shown filled with water to the level 00, this being maintainedconstant due to the described distribution of steam and water inrelation to the steam output of the drums. I

The front bank of tubes 16, which generates about 66% of steam, is soarranged that the first, third, fifth, etc., rows of tubes will lead tothe front drum 1, and the alternate or second, fourth, etc., rows to themiddle drum 2, liberatin about 33% of the steam to each drum 1 and 2 bythis distribution.

It will be noticed that the tubes of the bank 16 that are exposed to theradiant heat of the fire and therefore generate most of the steam, enterdrums 1 and 2 above the water line,

and they are shown discharging the slugs of water and steam againstplates or baffles 17, which break up the steam velocity and the slugs ofwater, maintaining the steam and water spaces of the drums in arelatively calm and quiet state.

The middle bank of tubes 18 deliver approximately 20% of steam andwholly to drum 2. This flows through circulating tubes 19 to drum 3.

The pressures in the three drums are nearly equal, and about ita of thesteam is taken from each drum, either through a dry pan 12 or direct bya longitudinal series of tubes 20, connecting to steam outlet orcollector 21.

Fig. 3 shows a proposed semi-vertical water tube boiler with two drums,filled with water to line 0-0, and arranged with a front bank of tubes22with alternate rows leading to drum 1 and the next row to drum 2, anarrangement that will deliver approximately of the steam to each drum.The arrangement provides for tubes 23 connecting direct from the dry pan12 in each drum to superheater collector header 24. Each drum isequipped with safety valve outlets 13 so arranged that the selection ofdry steam by the dry pans 12 will not be interfered with when either ofthe safety valves operates, preferably by taking off from the steamspace direct and not through the regular steamoutlet or dry pan.

' The usual cross drum boilers are limited to one drum, and this islimited in diameter to about inches owing to comparative expense withother boilers, shipping weight etc.

In Fig. 1 is shown a modern cross drum boiler, with an additional drumprovided, and with a proposed high pressure and high output forged steelsectional header boiler. \Vhen made with two or more drums such boilermay be filled with water to level 0O, which is maintained in a calmstate of maximum density and hydrostatic head as described. The waterdescends through one Or two water supply tubes 25 leading from the drumsto a lower header 27. The water passes downward and thence into andthrough the first and second banks of boiler tubes 26 and 26", wheresteam is generated, passing up to the inclined sectional upper header27i The steam and slugs of water rising in one of these headers are thenpassed through tubes 28 to the first drum 1. The next alternatesectional header may connect by tubes 28 to drum 1; the steam and waterslugs being then passed through tubes 29, located in drum 1, and throughtubes 30 leadin to drum 2 or exterior connections could be made as shownin Fig. 9 at 28" which is a more practical arrangement.

The steam and water slugs are thereby discharged substantially equallyinto the two drums above the water line, striking louvre bafiies 31; thesteam is liberated and the water falls like rain on the Water held instorage, thus drying the steam. The water in circulation is relativelycalm, at maximum density and hydrostatic head,,thus assuring rapidcirculation.

The two or more drum cross drum boiler of Fig. 4, with this improvement,permits sometimes double the steam output, without increasing themoisture content in the steam.

The steam is collected uniformly the full length of each drum by dr pans12, and then passes direct through tubes 32 to a steam outlet header orsuperheater collector 33. It has been the practice to place safetyvalves over dry pans, and when such valves operated there has been anexcessive Velocity of steam entering the dry pan, and this has picked upand entrained much moisture. This invention includes a dry pan 34arranged with a loose sleeve 35, extending through the dry pan, as shownin Fig. 5; by this arrangement, safety valve operation cannotsubstantially increase the moisture content in outgoing steam, for ittakes steam direct from the drum steam space and not from the dry pan.

The equalization of steam outflow from the several drums may becontrolled by the adjustment of the dry pan inlets, in a manner as shownin Figs. Gand 7 Thus the steam inlet area. 36 may be adjusted as in Fig.6 by a threaded bolt 38. The adjustment of the inlets to the dry pansalso gives control as sisting to maintain a uniform water level in allthe drums. The control of steam inlet area 36 to each dry pan 37 may bemade from outside of drum as in Fig. 7 by a threaded nut 39, whichraises and lowers a bolt 40 supporting the pan 37. V

The present invention may be summed up [I as relating to the class ofboilers having a' system of water tubes ex osed to the furnace and aplurality of elevated sieam-and-water drums each receiving steam fromand supplyin g water to the tube system; and as comprising thecombination with such drums, each having its steam space substantiallynot smaller than its water space, and such tube system, the same havingconnections distributing steam separately to the drums, preferably atrates approximately proportional to' the volumes of the steam spaces ofthe respective drums, and the connections to each drum entering the samesubstantiall or uniformly along its entire length, and said drums havingsteam outlets from the steam spaces thereof adapted to deliver steamtherefrom, preferably at rates approximately proportional to the volumesof the steam spaces of the respective drums, and the outlets from eachdrum leaving the same, or the steam space thereof, substantially alongits length so as to collect steam substantially uniformly over thelength of the water space. By the described arrangement of the inletsand outlet-s of each drum the flow of steam from the inlets to theoutlets is a substantially transverse and short flow, and therefore atrelatively low velocity, and preferably at aproximately equivalentvelocities in the several drums; and there will be no high speed racingof steam longitudinally in the steam space of any drum to reach theoutlet thereof, in consequence of which full opportunity is afforded forthe precipitation of moisture,

and the steam flow transversely through the drum will not tend to pickup the water from the water space; consequently the dryness of the steamis maintainable even with greatly increased generation of steam to meetfluctuating demands.

In stating the apportioning of distribution of steam to the severaldrums by the relation thereof to the steam spaces of the drums. this hasreference to the preferred or minimum steam spaces which. in each drum,may be substantially equal to the water space, or one half of the volumeof the drum; it is not intended to exclude an arrangement otherwiseequivalent of that illustrated but wherein the steam space is enlargedto provide excess volume and corresponding increase in steam dryingeffect.

The arrangement of the steam outlets from the steam space of each of thedrums, namely along substantially the entire length of the drum, may beafforded in various ways, for example by an elongated series of separateoutlet pipes, but is illustratively shown as effected by the use of adry pan, pipe or collector, the interior or passage of which is notconsidered as part of the steam space-of the drum. The dry pan extendssubstantially the entire length of the drum so that the steam may flowinto the dry pan passage from the steam space along substantially itsentire length, avoidini. the usual longitudinal flow and inherent highvelocity.

The outflow of steam from the steam spaces of the drums to whichreference has been made is a final outflow, and has no reference to amere circulating connection from drum to drum. such as the pipes 9 or 9of Fig. 1 or the pipes 19 of Fig. 2, wherein may occur a minor orpressure equalizing flow between drums. The steam outlets of thisinvention extend fom the steam spaces of the drums into the dry passagesand thereafter do not reenter such steam spaces, but pass on to thefinal outlet. Thus in Fig. 1 the final steam outlet 113 receives steamfrom the steam spaces of all of the drums without the necessity of thesteam so received from any drum having to pass through the steam spaceof any other drum.

The water level is normally substantially the same in all of the drums,as is customary in the class of boiler referred to, and the level maybedetermined and controlled in any usual manner, for example underobservation by means of a water gage 101 attached to one of the drums,or by an automatic boiler feed regulator. Preferably the water volume ofeach drum is maintained small to ensure fast steaming qualities, whilemaintaining enou h water to ensure proper recirculation to the boilertubes. Relativel small drums therefore may be employed, wherein thewater and steam spaces are approximately equal. The several drums arepreferably of the same size, but if unequal the one with the largersteam space will preferablv receive steam at proportionately greaterrate as stated.

Having described several illustrative embodiments of the invention it isstated that it is not intended to limit the invention to thespecifically illustrated features of combination, arrangement orstructure except to the extent set forth in the accompanying claims.

What is claimed is:

1. A steam boiler of the class having a system of water tubes exposed tofurnace heat and a plurality of elevated steam-and-water drums alldelivering to a common final outlet and each receiving steam and waterfrom and supplying water to the tube system and each such drum havingboth its inlet and its outlet connections distributed along its lengthwhereby to secure transverse flow and substantially to avoidlongitudinal flow within the drum so to minimize the steam velocitywithin each drum; and said boiler characterized by the particularcombination of said steam-and-water drums and said water tube systemwherein the steam connections extending from the tube system to therespective drums are arranged or apportioned to distribute to therespective drums the steam generated in the tube system at rates byweight approximately proportional to the volumes of the steam spaces ofthe respective drums and the steam outlets from the respective drums areadapted. to deliver steam therefrom at rates also approximatelyproportional to the respective steam spaces'whereby there will bemaintained within all of said drums transverse flow of steam from inletsto outlets at approximately equal and therefore uniformly minimumvelocities.

2. A steam boiler of the class having a system of water tubes exposed tofurnace heat and a plurality of elevated steam-and-water drums alldelivering to a common final outlet and each receiving steam and waterfrom and supplying water to the tube system and each such drum havingboth its inlet and its outlet connections distributed along its lengthwhereby to secure transverse flow and substantially to avoidlongitudinal flow within the drum so to minimize the steam velocitywithin each drum; and said boiler characterized by the particularcombination of said steam-and-water drums and said water tube systemwherein the steam connections extending from the tube system to therespective drums are arranged or apportioned to distribute to therespective drums the steam generated in the tube system at ratesapproximately proportional to the volumes of the steam spaces of therespective drums whereby there will be maintained within all of saiddrums transverse flow of steam at approximately equal pressures and atapproximately equal and therefore uniformly minimum velocities.

3. A steam boiler constructed and operating as in claim 2 andcharacterized further by a safety valve system comprising a separatesafety valve connection for each drum and each of the several safetyvalve connections being connected into its drum to receive steamdirectly from the steam space of the drum rather'than from or throughthe aforesaid steam outlet connections of the drum.

4. A steam boiler of the class having a sysflow within the drum so tominimize the steam velocity within each drum; and said boilercharacterized by the particular combination of said steam-and-waterdrums and said water tube system wherein the steam connections extendingfrom the tube system to the respective drums are arranged or apportionedto distribute to the respective drums the steam generated in the tubesystem at rates approximately proportional to the volumes of the steamspaces of the respective drums and the steam outlets from the respectivedrums are adapted to deliver steam therefrom at ratesproportional to thereceipt of steam therein from the tube system whereby there will bemaintained within all of said drums transverse flow of steam atapproximately equal velocities, and approximately equal water densitiesand levels.

5. In a boiler of the class having a system of water tubes exposed tofurnace heat and a plurality of elevated steam-and-water drums eachreceiving steam from and supplying water to the tube system, thecombination with such drums, each drum having substantial steam andwater spaces, and such tube system, the same having connectionsdistributing steam separately to said drums, and such connections toeach drum entering the drum at inlets arranged along substantially theentire length of the drum, and each of said drums having a steam outletconsisting of a longitudinal steam collecting dry passage Within theupper part of the steam space provided with a port or ports extendingsubstan- 1

